Proof of concept on Ant Colony Optimization for solving a 15puzzle problem.

Although this problem is easily solved using A* search, an example of how this problem could be solved using ACO was developed for a mathematics class, it was done in a couple of days, and I struggled a bit with multiprocessing so at the end I got better results without it given the limited time I had for the task. (It's on my todo!)

It uses 6-6-3 PDB (Pattern Database) as optimal heuristic.